Typical windshield washer/deicer compositions have the property of melting ice that forms on windshields. Windshield washer/deicer fluids generally contain water, a water miscible alcohol to depress the freezing point, a surfactant for lubricating, and a colorant. Many deicer or anti-icing compositions rely upon an alcohol, in particular methanol, to impart the ice-melting properties to the compositions.
However, the primary purpose of such compositions is to assist the windshield wipers in the removal of vision obscuring materials from a windshield. Vision obscuring materials include dirt, grime, bugs, sap, frost, ice, snow and combinations thereof. Although these compositions can be used to assist in the removal of accumulated frost, ice and/or snow, they have typically failed to prevent or impede the formation of frost. Moreover, none of these compositions are known to provide the dual function of preventing frost formation while still making it easier to remove any frost, snow and/or ice that has accumulated.
‘Frost’ as used herein refers to the deposit of minute ice crystals formed from the condensation of water vapor at a temperature below freezing. It will be appreciated that frost is often seen on the windshields and windows of an automobile exposed to temperatures at or below freezing. Although frost can develop within a few hours or less, drivers often experience it in the morning.
Frost is undesirable because it can result in increased driver delay and/or the wasteful application of heat energy. Frost is often adhered to a window surface so strongly and in such amounts that forceful mechanical action and/or the extended application of heat is necessary for its removal. Drivers would thus prefer to be met with frost-free windows, windows having greatly reduced amounts of frost thereon, and/or frost that is more easily removed, i.e., less adhered to the windshield.
The term ‘winter precipitation’ as used herein refers to frost, snow, ice, and mixtures thereof. It will be appreciated that in some cases, frost formation is accompanied by the accumulation of snow, ice, and mixtures thereof. In all cases, it would be desirable for drivers to find it easier to remove any accumulated winter precipitation from an automotive windshield or window. Windshield as used herein refers to any glass panel that a vehicle driver or passenger looks through or at or which light is desired to pass through, such as an exterior automotive lighting and mirrors.
Drivers thus particularly desire a method whereby the accumulation of frost on a windshield could be either entirely prevented or greatly reduced while simultaneously making it easier to removal any accumulated winter precipitation. The terms ‘prevent’ or ‘impede’ as used herein refer to the reductions in the area, thickness, hardness, and/or degree of adhesion of any accumulated winter precipitation. It will be appreciated that reductions in the degree of adhesion of any accumulated winter precipitation to a windshield facilitate the removal of such winter precipitation from said windshield. That is, it becomes easier to scrape, rinse, wipe, and/or brush the winter precipitation from the windshield.
Compositions comprising alkyl-substituted disilicanes and alkoxy-substituted di- and tri-silicanes have been described as useful as water-repellent compositions for use on windshields. Mono-alkoxy silicanes have been described as useful as a bonding composition for use with water-repellent compositions comprising a hydrocarbon wax and a polyamide. No water-repellency is attributed to the silanes themselves. Finally, particular silicane copolymers are described as useful for providing water-repellency, as well as facilitating ice removal from windshields.
Thus, there continues to be a need for compositions and methods for preventing the formation of frost while simultaneously making it easier to remove any accumulated winter precipitation from a windshield, especially in regards to the prevention of frost over a period of hours, such as overnight.